Measurement of D[superscript 0] − [¯ over D][superscript 0] Mixing Parameters Using D[superscript 0] → K[subscript S][superscript 0]π[superscript +]π[superscript −] and D[superscript 0] → K[subscript S][superscript 0]K[superscript +]K[superscript −] Decays

Abstract

We report a direct measurement of D[superscript 0]-[ ̄ over D][superscript 0] mixing parameters through a time-dependent amplitude analysis of the Dalitz plots of D[superscript 0]→K[superscript 0][subscript S]π[superscript +]π[superscript -] and, for the first time, D[superscript 0]→K[superscript 0][subscript S]K[superscript +]K[superscript -] decays. The low-momentum pion π[superscript +][subscript s] in the decay D[superscript *+] →D[superscript 0]π[superscript +][subscript s] identifies the flavor of the neutral D meson at its production. Using 468.5fb[superscript - 1] of e[superscript +]e[superscript -] colliding-beam data recorded near √s=10.6 GeV by the BABAR detector at the PEP-II asymmetric-energy collider at SLAC, we measure the mixing parameters x=[1.6±2.3(stat)±1.2(syst)±0.8(model) ] ×10[superscript - 3], and y=[5.7±2.0(stat)±1.3(syst)±0. 7(model)]×10[superscript - 3]. These results provide the best measurement to date of x and y. The knowledge of the value of x, in particular, is crucial for understanding the origin of mixing. © 2010 The American Physical Society.